Front end rattle

I have a 2001 Chevy Silverado 4x4 that had developed a front end rattle that travels up through the steering column when I turn the wheel. It does it sitting still and driving. Any ideals on what it could be? My visual exam of the front end revealed nothing, but I could be over looking something. Any help or suggestions would be greatly appreciated.

You probably are hearing the intermediate steering shaft noise. Have the dealership put a lubrication kit on it. This should fix the problem. Good Luck.